A gas turbine includes an air compressor that compresses outside air and generates compressed air, a plurality of combustors that combusts a fuel in the compressed air and generates a combustion gas, and a turbine that is driven by the combustion gas. In the gas turbine, since a combustion liner of the combustor, a blade or a vane of the turbine, or the like is exposed to the combustion gas of high temperature, it is necessary to protect the high temperature portions from heat of the combustion gas by cooling the high temperature portions.
Patent Document 1 below discloses a cooling system for cooling a transition piece (combustion liner) of the combustor which is a portion of the high temperature portions of the gas turbine. The cooling system includes a cooler that cools compressed air extracted from an air compressor and a cooling air compressor that pressurizes the compressed air cooled by the cooler and supplies the compressed air to a transition piece of a combustor as cooling air.